><So we arrive back at the Great Filter problem. The dinosaurs lived on >earth for millions of years, but never evolved into tool-using creatures. > Why?>Terence McKenna has suggested that when our ancestors discovered >psychedelic mushrooms, that stimulated them to start thinking, talking, and >using tools. That was when they broke through the filter and started >making progress. Without mushrooms, we could have been stuck in an >evolutionary cul de sac for eons, like the dinosaurs.>

I watched a show once where they suggested that it was the introduction of
seafood into the proto-human diet between 4 and 7 million years ago that
triggered the increase in intelligence. The diets of most primates are
lacking in several important neuro-active and bio-active compounds directly
involved in higher brain functions. Many of these compounds are generally
only found abundantly in nature in seafoods.

Several studies have been done on the impact of diet on intelligence. The
lack of seafood in a diet (especially from saltwater sources) has been shown
to have direct impacts on the average intelligence of a population. These
compounds are especially important during childhood.

Iodine is a case in point. Naturally, iodine is found almost exclusively in
seafood sources. There is a region in inland China where 1 in 8 people is
technically mentally retarded, and few people in the region have "normal"
intelligence. As a whole, the average IQ of people in this region is far
below the human average. The reason has been determined to be iodine
deficiency. They have no access to sources of iodine in their diet. They
are genetically normally, but lack of a key compound has rendered them less
intelligent than their genetically determined capability. Unfortunately,
the effects of this are structural and irreversible.

Fortunately for many developed countries, iodine is artificially introduced
into the diet so that this is not a problem. This may also be why countries
with high seafood diets also are among the highest in raw IQ as well.

The introduction nootropics into the proto-human diet was very likely
responsible for the advance of our species. I don't know too much about the
mushroom theory, but the seafood theory does seem plausible. AFAIK, humans
are the only primates that eat seafood.